Forest fragmentation has resulted in decreased wildlife habitat, which has triggered conflicts with humans due to the use of the same plants. This has been particularly contentious with the tapanuli orangutan. Research of the tapanuli orangutan (Pongo tapanuliensis) habitat is very limited. The aims of this research is to examine the latest habitat conditions, such as land cover, composition of vegetation, feed plant, and habitat carrying capacity to provide recommendations for habitat management in developing a mitigation policy of the human-tapanuli orangutan conflict. The research location is focused on the area of human-orangutan conflict in the Batang Toru Landscape in South Tapanuli Regency, which took place from August to December 2019. Vegetation analysis was conducted using the strip transect method with a total of 294 plots (11.76 ha). The number of species at the pole and tree levels were high with 149 species (46 families) and diversity index (H') > 3. Eighty feed plant species were found and expected to support the growth of the orangutan population of 247 individuals. The density and diversity of cultivated plant species in the buffer zone were high and consumption by orangutans resulted in human-tapanuli orangutan conflict, especially on durian (Durio zibethinus Murray). Conflict with humans will cause stress and disruption to the growth of the tapanuli orangutan. We recommend habitat management to mitigate conflict through patrols for monitoring habitat destruction in conservation forests, enrichment of feed plants in Forest Management Units, cultivation of orangutan non-food crops on community lands, and building a corridor with orangutan food crops with fruits that are not utilized by humans.

Deforestation will cause bird species be endangered. The purpose of this research is to find the information of the effect of plant composition on bird species population and diversity which can be used for developing bird conservation program in Batang Gadis National Park (BGNP). This research was conducted in the year of 2006-2007 in the zones planned for the BGNP. Data were collected with the strip transect method for vegetation and the variable circular-plot method for bird. The number of plant species identified on 2.8 ha of research areas were 158 species. The highest plant composition consisting of total density, total frequency, and total dominancy components was found in sub-montana primary forest. The bird species diversity indices and the abundance indices ranged from 2.9 to 3.9 and from 27.2 to 69.1 respectiely. Bird population density was 1.06 individual/ha. The plant composition influenced 90.4% of diversity, 94.3% of abundance indices, and 67.3% of density value of bird species.

Abstract. Kuswanda W, Harahap RH, Alikodra JS, Sibarani R. 2020. Nest characteristics and populations of Tapanuli orangutans in Batangtoru Landscape, South Tapanuli District, Indonesia. Biodiversitas 21: 3398-3406. Tapanuli orangutan (Pongo tapanuliensis) has been threatened to extinction due to conflicts with humans. Information on the orangutan characteristics in conflict areas at the Batangtoru Landscape is needed. Our research aimed to analyze the characteristics of nests, nest trees, and estimation of orangutan populations in conservation forests and buffer zones to develop conflict mitigation strategies in the Batangtoru Landscape, South Tapanuli District. A line transect method was used to count orangutan nests on 49 transects, starting from June 2019 to January 2020. Data were analyzed with descriptive statistics, frequency tables, Spearman correlation (rho), and the equation by (van Schaick et al. 1995). Tapanuli orangutans make nests at the height of 14.01 meters (90% CI = 13.37-14.67 meters), and most use the main stem as nest support. Tree nests of 35 species (17 families) were identified, with the highest frequency in (Durio zibethinus Murray), especially in the buffer zone. Correlation between nest tree diameter, tree height, and canopy area was significant (p <0.01, n = 83). The estimated orangutan populations in conflict areas were 155 individuals (95% CI = 121-187), and the highest was found in Dolok Sibualbuali Nature Reserve buffer zones. Mitigation strategy of human-orangutan conflict that needs to be realized is the non-cash compensation guaranteeing the community does not disturb orangutans on their land. The compensation forms can be the provision of seedlings and fertilizer for plants, agricultural machinery, knowledge to land management, and orangutan ecotourism development. Nest and feed trees enrichment can be carried out in production forests bordering with conservation area.

Current population of Sumatran orangutan (Pongo abeliiLessonkg/ha/hari (berat basah) atau 14,8 kg/ha/hari (berat kering). Nilai produktivitas buah dengan memperhatikan musim berbuah diperoleh antara 2,2-13,1 kg/ha/hari (berat basah) atau 0,9-5,6 kg/ha/hari (berat kering). Nilai konsumsi orangutan diperkirakan sebesar 6,2 kg/hari/ekor. Berdasarkan produktivitas daun dan buah diperoleh daya dukung habitat sekitar 47-56 ekor.Kata kunci : Populasi orangutan, Pongo abelii Lesson, Cagar Alam Dolok Sibual-buali, produktivitas pakan I. PENDAHULUAN A. Latar BelakangDaya dukung habitat adalah kapasitas optimum suatu habitat untuk mendukung populasi satwaliar tertentu, sehingga dapat hidup secara normal. Alikodra (1990) menambahkan bahwa daya dukung habitat merupakan batas atas pertumbuhan populasi, sehingga jumlah populasi tidak dapat berkembang lagi. Banyak kegagalan dalam pengelolaan satwaliar, karena kurangnya perhatian terhadap kemampuan habitat dalam mendukung pertumbuhan suatu populasi satwaliar. Suatu habitat akan dapat menampung sejumlah satwaliar sesuai dengan daya dukungnya.Pendugaan daya dukung habitat sangat diperlukan terutama pada populasi satwaliar yang statusnya sebagai satwa *) Diterima

<p>The population of Sumatran orang utan in natural habitat has been declined and threatened with extinction. The orang utanreintroduction program is expected to increase breeding and population in nature. This study aimed to analyze the important value index of vegetation as well as the diversity and abundance species of Bukit Tiga Puluh National Park (BTNP) as dietary sources for reintroduced Sumatran orang utan. The research was conducted during two years from 2015 to 2016. The data collection for flora characteristics is done through the vegetation analysis with strip transects method. Plots were selected by stratification method based on the resort management and the land cover, like primary and secondary forests. Total flora species on a plot of 2.8<br />ha were identified about 301 species. The highest variation found in Suo-Suo Resort (139 species) and the lowest in Talang Lakat  Resort (82 species). The dominant species have been found were Eugenia grandiflora O. Berg, Macaranga lowii King ex Hook.f., Shore iliginosa Foxw., and Tarrietia rubiginosa Kostern. Vegetation chararacteristic to be identified were tree density of 350-552.5 individuals/ha, species diversity index of 2.86-4.19, and abundance index of 32.1087.35. It also identified that vegetation characteristic among resort and land cover were different (p &lt;0.05). Moreover, there were about 110 species of tree plants including of 31 families that found as dietary sources for orang utan and leaves became the highest plant parts which consumed by orang utans (41.8%) compared to other parts. Based on area size, ecosystem types as well as vegetation composition and variation, BTNP may support the increasing population of orang utans. However, there needs to be considered that other<br />aspects such as high human activity within the conservation area, particularly by Talang Mamak tribe communities, may cause unsuccessful achievement on reintroduction program of orang utan.</p>